Explosive device



Aug. 26, 1947. N. M. HOPKINS EXPLOSIVE DEVICE Filed March 9, 1942 3 Sheets-Sheet l ff fill/ lNyENToR Aug. 26, 1947. N, M, HQPKlNs 2,426,269

EXPLOSIVE DEVICE Filed March 9, 1942 3 Sheets-Sheet 2 FIG4 8 a F365 ff@ g au AUS- 25 l947- N. M. HOPKINS EXPLOSIVE DEVICE Filed March 9, 194.2

3 Sheets-Sheet 5 R AvO T ,N E V m EHLOSIVE DEVICE Application March 9, 1942, Serial No. 433,989

(Cl. b-24) 3 Claims. i

This invention pertains to a compartmented safety cartridge for farm, municipal and industrial blasting, comprising inexpensive and readily procurable constituent parts, less hazardous in putting them together in the process of manufacture, as well as in transportation, storage and use, than dynamite and dynamite cartridges, as well as certain other explosives packaged for such purposes.

It is a special object of this invention to provide a practical cartridge with an outer and an inner chamber fashioned to keep separate, and also to conveniently bring together prior to use, the liquid components, or semi-liquid components, of a liquid or semi-liquid explosive.

It is also a special object of this invention to produce a double-safe cartridge when desired, one fashioned to not only keep safely separated the liquid component parts of a liquid explosive until the time of use, but to allow 'its contents, after being brought together, to harmlessly disappear by evaporation after a period of time, if the cartridge is not iired within a speciiied period of time. This double safety feature is now enjoyed in the use of liquid air or liquid oxygen, explosives comprising a combustible body, the liquid air or liquid :oxygen evaporating within a period of time, leaving the harmless combustible body behind if the charge is not fired. Liquidair and liquid oxygen, however, cannot be kept conned as can liquid nitrogen tetraoxide, and therefore the present cartridges utilizing this material are a distinct advancement in this art.

It is a particular object of this invention to provide methods, ways and means for safely making, storing and using a liquid or semi-liquid explosive comprising liquid nitrogen tetraoxide and one or more combustible substances such as benzol, nitro-benzene, gasolene, kerosene, carbon di-sulphide, certain greases and the like,

It is also a particular object of this invention to produce a practical blasting cartridge devoid of all hazard in manufacture, and which is periectly inert to rough handling and to sharp accidental blows, unless or until the inner chamber of the cartridge is deliberately opened, by the sudden and rapid rotation of the outer casing, a special cooperative mechanical device being essential for such sudden and rapid rotation of the outer casing.

It is also a particular object of this invention to produce a practical blasting cartridge devoid o! all hazard in manufacture, and which is perfectly inert to rough handling and to sharp accidental blows, unless or until the inner chamber of the cartridge is intentionally opened through the agency of a special long-shanked key, fashioned to be inserted in the detonator well-way, and to revolve the stem of the inner chamber opening device.

It is a particular object of this invention to provide a cartridge for farm, municipal and industrial blasting, comprising a special pressureresisting casing with a pressure-resisting wellway in the top, or cover member, or bottom member, or a pressure-resisting recess in a side wall of said pressure-resisting casing, for the reception of a detonator, thereby obviating the more or less hazardous necessity of cutting into a package and improvising a hole or recess in the material of the explosive proper, as is now necessary for the insertion of a detonator into the dynamite of a dynamite cartridge.

It is also a special object of this invention to produce safe and practical blasting cartridges with the foregoing convenient characteristics and security to life and limb, and also of graded strengths and graded velocities of rates of detonation; that is to say, cartridges suitable for ditch, tree trunk, and soil blasting, for example, on the one hand, Where a comparatively slow, heaving action is desired, and for well shooting and rock blasting, for example, on the other hand, where a comparatively fast and shattering action is desired.

It is also a special and particular object of this invention to provide methods, and Ways and means for quickly ascertaining at any time after manufacture that the inner chamber is still here metically closed or, on the other hand, to show that the inner chamber has been opened, and that consequent admixture of the liquid or semiliquid component parts of the liquid or semiliquid explosive has taken place.

It is a special object of this invention to produce a practical and structurally safe cartridge casing, to not only hermetically enclose the several liquid or semi-liquid component parts of the contained explosive, but to resist rupture with a suitable factor of safety in all climates, since said component parts comprise a liquid gas, namely the liquid nitrogen tetraoxide, which has a vapor pressure at certain summer temperatures and tropical climes well above the pressure of the atmosphere at sea level.

It is also a particular object of this invention, by utilizing the applicants former teachings, to make safe and practical the formation of a comparatively sensitive and comparatively high power liquid or semi-liquid explosive from a comamazes It is also a particular obiect of this invention to render as small and therefore as cheap aspossible the inner chambers of my compartmented cartridges. This through the foregoing particular object since the forming of acomparatively sensitive and comparatively high power liquid or semi-liquid explosive, from a comparatively insensitive and comparatively low power liquid or semi-liquidA explosive, fashion and use smaller and less expensive inner chambers for the holding of the liquid nitrogen tetraoxide. This because a portion of the liquid nitrogen tetraoxide is dissolved and distributed in one or more of the bustible substancesin the outer-,casing Especially is it possible toA use a smaller inner chamber when I use nitro-benzene in the outer casing,A

which compound requires the minimum of the liquid nitrogen tetraoxide to make the comparatively sensitive and comparatively high powered explosive therewith. It requires less liquid nitrogen tetraoxide because nitro benzene already has a NO: radical in its molecule. In such practice I elect to use a sheet iron casing for the outer shell of the cartridge in the place-of such substitutes therefor as impregnated pasteboard presently to be described.

This invention is a continuation in part of my. copending United States patent application led May 8, 1939 under the Serial Number 272,434, entitled Liquid explosive. now Patent No, 2,298,- 255, dated October 6, 1942.

In the present patent application Figures 7, 8, 9,

liquid or semi-liquid com-A enables the applicant to4 design of one' of my copied by the draftsmanfrom my co-pending United States patent application, previously mentioned, and illed May 8, 1939. i

Figure 8 is a sectional view through -another blasting canisters, likewise copied, from the aforesaid patent application.

Figure 9 is a diagrammatic cross section through Figure 7, also copied from the aforesaid patent application, and

Figure 10 is a detail of one design of detonator well-way for one design of my blasting canisters,

.also copied by the draftsman from the aforesaid patent application.

the above-cited copendingpatent application.

With the lforegoing enumerated objects in view, as well as certain other objects which will become apparent as the description'proceeds and the drawings are studied, the invention consists in the novel parts and principles, methods, ways and means of producing cartridges, canisters, and explosive fillers therefor, all as herein set forth and particularly pointed out in the claims.

Referring to the accompanying diagrams and drawings forming a part vof this specification, in which like numerals designate like parts in all the views:

Figure 1 represents a view in elevation of one design ofv one of my double-safe blasting cartridges showing at an end the shortened lead wires of an electrical detonator. as well as a portin of said electrical detonator inserted in the specially designed and fabricated well-Way for quick, convenient and safe. reception of the said electrical detonato f Figure 2 is a sectional view through this blasting cartridge, showing assembled the simple parts all designed to Ibe made by automatic or/and semi-automatic machinery from inexpensive material, iron, for example, impregnated pastebpard, and wood.

Figure 3 is apartial elevational view, as well as a sectional view through a part of a casing, showing the inner chamber in openposition.

Figure 4 is a sectional view through a somewhat diiferent design of a double-safe blasting cartridge. f f

Figure 5 is a-sectional view through a modified design of the foregoing blasting cartridge.

Figure 6 is a sectional view through an elaborated design of the foregoing blasting cartridge.

With further-reference to Figure l, 2| is a crimped-on screw-threaded, metal end member, of black iron, tinned iron, aluminum, or sheet steel, for example, since all 'of'these metals are passive to allof the constituent parts of the contents of the cartridge; and 22 is a screw-threaded metal cap member providedwith a metal of like composition to the foregoing, detonator wellway, hermetically attached to, as well as mechanically attached to, o'r'formed as an integral part of, 'the cap member 22, an end of which well way is shown at '24, said threaded metal cap member 22 being fashioned to screw onto the crimped-on member 2l with a gas and liquid tight ilt, comprising'a gasket or cement sealing or both. V f

23 is, an end of a standard electrical detonator cement, inposition and furthermore attached to said casing' by pin members 28, 28.

With further reference to Figure 2, here the top of the metal detonator well-way 24 is shown as a continuation of the well-way tube 29, expanded in the manner shown'at Il to make a 'slip-proof, and gas and liquid tight junction with -`c1o`sure disk member 35 with a boss member 38,.

the top of the metal cap member 22; andl Il is a reinforcing collar member also in this particular design of rolled impregnated paper and glued or cemented in position, saidcollar reinforcement being positioned to reinforce the somewhat weakened zone of the pasteboard casing-or tube 20, due to the crimping on of the metal cap member 2|. Suspended from'an end of the metal wellway 29 is the heavy bevel edged closure disk member 32, attached to an end of themetal wellway with a forced` or threaded it (screw threads not shown)l,and consequently a mechanically as well as a gas and liquid tight closure. This wellway 29 and -bevel edged closure disk member 32 may of course' be fabricated in one-piece.

Within a Athreaded hole in` the boss member 33 is disposed the upper end of the ir'on or steell tie rod 34, threaded and screwed into position in,

the boss member 33 as shown. Aft the opposite end of the steel tie rod 34 is a heavy bevel edged drilled and threaded to receive thelower threaded end of the tie rod Il; and 31 is an extension and attened mass of metal, a part of the bevel edge Y closure disk member 35, to not only add weight and inertia. thereto, but to serve asa vane. This particular vane member may be quickly fabricated, as Iby-drop forging, prior to automatic or semi-automatic machining. 38 is a` metal tube ofiron, steel or aluminum, of suchdiameter asL to .allow the bevel edges of the aforesaid bevel f edged closure disk members to make automatia volume of liquid nitrogen tetraoxide, a liquid gas with a fairly substantial vapor pressure at summer temperatures (35 pounds to the square inch at a temperature of 104 Fahrenheit for example, and '70 pounds to the square inch at 140 Fahrenheit for example). Thus it will be seen that the threaded steel tie rod, perfectly passive .to the liquid gas, should be fashioned with its screw threads to withstand tension the equivalent to at least 70 pounds when the end closure members have a surface area of one square inch, with a suitable factor of safety-100 pounds or more for example.

At 4l the combustible substance or substances are shown in dotted lines. This combustible substance may be benzol, gasolene, kerosene, carbon disulphide, or certain heavy grease, or a combination of two or more of such combustible substances', for sensitivity and thermodynamic adjustment purposes, which combustible substances have a comparatively small vapor pressureless than one pound to the square inch at the summer temperatures given.

All of these remarks are especially pertinent at this time since it should be pointed out that a mixture, or more correctly stated, a. mutual solution of liquid nitrogen tetraoxide and benzol for example, reduces materially the. vapor pressure of the liquid nitrogen itetraoxide, the extent of the reduction in vapor pressure being dependent upon the proportions of the liquid gas to the benzol. In any event, that is to say in any mixture or mutual solution of the several substances enumerated, there will be a reduction in the resultant vapor pressure, so that the strength or resistance to rupture of the cartridge casing 20, together with its end members 22 and 21, need not be so great as that of the tubular member 38 and the closure end members 32 and 35. All of applicants cartridges are fashioned and tested for internal pressures based upon theoretical calculation of and practical check measurements of the several mixtures or mutual solutions used in the fabrication of the cartridges. l

To open the inner tubular member or compartment in this particular design of cartridge, it is necessary togrip the outer casing 28 with a friction grip, and to axially impart thereto a sudden and rapid rotative force as may .only be properly applied through the agency of a special mechanical device, a simple portable design for which has been worked outby the applicant. It will now be appreciated from an inspection of this system that a sudden axially applied and rapid rotary movement of the casing will unscrew the steel rtie rod 34 from the boss 36 of the bevel edge closure member 35 because of the mass and inertia of the metal tube 38 acting in harmony with the mass, inertia, and vane action of the said bevel edged closure member 35, the vane 31 being retarded in rapid rotation by the combustible iiuid, semi-fluid or grease 4I.

With further reference to Figure 3, in this view the interior members 32, 38 and 35 are shown dropped apart, as would be the case when the interior chamber and the surrounding casing were properly lled with their respective fluids, and the outer casing given a suitable smart and sudden rapid spin. Itis believed that no further comment is needed in connection with this illustration, except to say that the tube 38 may be suitably retarded from appreciable longitudinal movement.

With further reference to Figure 4, here 42 is a different design of end` closure member of impregnated wood or composition with the detonator well-way screwed in at 43 against a shoulder 44, the lower end 45 of said well-way being driven into or screwed in-to the opening 46 of the metal closure member 41 with a mechanically, as well as a gas and liquid tight fit, the member 41 having a groove 48 turned into the 'metal member to receive, with a gas and liquid tight fit, the upper end 49 of the metal inner tube 5U, a sealing compound being used in this connection. The lower end 5-l of the tube 50 enters the groove 52 of the end closure member 53, said groove also being filled with a sealing compound. Turned within the bore of the tubular member 50 is the groove 54, and 56 and 55 are a pair of steel spring members rigidly attached at ends to the closing member 53 and fashioned through the agency of sharp V bends as illustrated to enter the groove 54 when the closure member 53 is thrust oi the end 5| of the tube 50 by the turning of the threaded steel rod 51 screwed into the threaded boss 58.

The theaded steel rod passes through the closure member 41, unthreaded, with a gas and liquid tight t and terminates in a square or polygon shaped head member 55, fashioned and positioned to receive a recessed end 88, to match the head member 59, of the shank 6| of the key 62. It will now be evident from inspection that by means of the key 62 inserted in the detonator Well-way, that the interior system may be unscrewed, that is to say, the closure member 53 may be forced off the end 5l of the tube 50, and that the spring members 58 and 55 not only prevent the closure member 53 from revolving and thereby defeating the ejection action, with the steel rod 51., but by engaging the groove 54 pulls the upper end 49 of the tube 50 out of the groove 48 in the top' closure member 41.

In order that the manufacturer, shipper, agent, purchaser, or user, for example, may know when the inner tube 50 has been opened, either accidentally or purposely, thereby discharging the liquid gas contents, I may elect to insert in an end closure member of the casing 20 a zinc electrode member 63 pressed, screwed, or otherwise inserted with a mechanical and a gas and liquid tight fit into the wooden or composition end closure member 64. In this connection let us consider that the well-way tubular member 65 is made of `iron or steel, and it will then be appreciated that with only benzol, gasolene, or grease, for example, in the casing 20, there will be practically no chemical and consequently no galvanic action on the zinc electrode member 63, even if a copper wire 68 has one end pushed into the interior of the detonator well-way, making electrical contact therewith, as shown, and has its other end connected with a milli-amperemeter 68 as shown, and a second copper wire connecting with the milli-amperemeter as shown with an exterior portion of the zinc electrode member 63.

With substantially no galvanic action upon the iron and zinc electrodes, there will be practically no movement of the pointer 61 of the milli-amperemeter 66. Should, however, the inner com.- partment 58 containing the liquid nitrogen tetraoxide be opened, accidentally or intentionally, the minute quantity of concentrated nitric acid which is present in the liquid nitrogen tetraoxide or/ and the increased quantity of nitric acid which would be formedthrough the moisture present in the benzol, gasolene or grease, would act upon the zinc electrode 63 in a different manner than it would act upon the, iron wall of the detonator well-way 65, and if cx'bnnected to a delicate electrical indicating instrument, a pocket milli-amperemeter, for example, would cause its pointer to be markedly deflected.

With further reference to Figure The cartridge illustrated here is substantially the same in design and structure as that shown in Figure 4, but the dimensions of the tubular inner chamber 50 are less, and this would normally impress the casual observer of the drawing as being unimportant. the contrary, this reduction in the size of the inner chamber is very important because it controls the volume of the nitrogen tetraoxide 40 which is to be mixed with an increased volume of benzol, gasolene, or grease, for example, 4| over the volume of benzol, gasolene or grease 4I in the cartridge shown in the preceding Figure 4.

The volume of the liquid nitrogen tetraoxide is decreased on the one hand because of the reduction in size of the inner compartment, and the volume of the benzol, gasolene or grease is increased, on the other hand, because the smaller inner compartment naturally displaces less of the combustible or combustible mixture in the outer casing 20.

With this change in dimensions of the inner compartment we secure, upon the mixing of the' liquid nitrogen tetraoxide with the liquid combustible bodies, an explosive at once less sensitive to shock, and at the same time one slower in its action and less powerful in its release of energy,l when exploded.

Such is not the case, however, for on- Again if we wish to most economically produce e, high-powered cartridge for rock shattering, we

will substitute a sheet iron outer casing for the pasteboard casing 20, and place in said outer casing a relatively insensitive and relatively lowpowered mixture of nitrogen tetraoxide and benzol, nitro-benzene, gasolene or grease, for example, in which case the contents of the relatively smaller chamber 50', which is the liquid nitrogen tetraoxide, are sufficient, when said contents are discharged, to convert the relatively insensitive and relatively low-powered mixture into a relatively sensitive and relatively high powered mixture. Thus it will be seen that the design shown in Figure 5 has very subtle possibilities.

The preceding remarks on low and high power mixtures respectively will be made clear from a study of my previously led co-pending U. S. patent application referred to hereinbefore. Since an explosive which may be ideal for one class of Work may be lacking in characteristics for another class of work, it will be seen that the proportion of nitrogen tetraoxide to the selected hydrocarbon may be varied in order to adjust the mixture as to its sensitivity to shock and/0r explosion. In practice applicant has found that substantially 2.18 volumes of the liquid gas (nitrogen tetraoxide for example) to 1 volume of the hydrocarbon (benzol for example) give the most effective high shattering results, using standard Trauzl lead blocks for testing purposes. On im-v pact tests using a 10 pound weight falling through foot drop on an explosive mixture placed upon a steel anvil, with several vials each containing a sampleof different admixtures of nitrogen tetraoxide and benzol ranging from 10% to 90% of the former to the latter, the following tabulation of detonating results was obtained:

.60 13 being either free to pass through the boss 8 10% Nam-No detonation. 20% vNeo4- No detonation. 30% NzO4No detonation. 40% NzOl-No detonation. 50% NaCl-No detonation.

NaCl-No detonation. K NaCl-Sharp detonation.

NzO4-Sharp detonation. mOi-Sharp detonation. 10. Neo4-No detonation.

wherefore it will be seen'that from 65% to 80% by volume o1' N204 when mixed with benzol produces detonation, and that 65% by volume is very close to the lower critical, and that -80% by volume is very close the the upper critical, limit.

Hence nitrogen textraoxide alone may be placed in one chamber of the explosive device herein contemplated, and the hydrocarbon alone may be placed in the other chamber, with perfect safety since each ofthese ingredients is non-explosive by itself; or, one chamber may contain a mixture of these two ingredients, while the other chamber may contain a certain amount of one of the ingredients, the mixture in the one chamber being in such proportion (up to 65% of nitrogen tetraoxide) as to provide a relatively insensitive and/or low powered explosive, and thecertain amount of one,of the ingredients in the other chamber being of such quantity that when added to the said mixture' there will -be a, change in the proportions of the two ingredients (up to 80% of nitrogen tetraoxide) resulting in an ultimate admixture thereof creating a, very sensitive and/or high powered explosive. Therefore, the ingredients within the two chambers may be varied to suit the purposes for which the device is intended, and the contents of both chambers will become admixed after opening the inner chamber. It` Will thus be appreciated that the applicant is able to produce a variety of safe cartridges to make, transport, store and use, as well as cartridges of graded sensitivities and graded powers.

With further reference to Figure 6:

Here We have substantially the same structure as in Figure 5, but elaborated for a greater factor of safety against rupture from vapor pressure and conducive to greater confidence by the user on the one hand, and greater safety after the elapse of a period of time on the other hand. Here 10' is a reinforcing band for greater safety in hot climates, and by means of a threaded extension 16 of the tie rod 51, having a head member 12, we have the casing heads 42 and 64 tied together under tension, the detonator well-way 65 serving the double purpose of convenient and safe receptacle for the detonatory and casing head brace'. The head member 12 may be a threaded nut for increasing the tension of the tie rod, the rod end be unscrewed for vent forming purposes, or peened over after assembly. When the rod 51 is free to unscrew from the nut 12 for vent-forming purposes, the threads 16 may 14 with a little clearance space, and in practice with this particular ventforming construction, the cartridge is rst re frigerated in a bucket of ice and water, for example, in order that the vapor pressure of the explosive mixture may be low and consequently.be of no risk to the hands of the user. .A stuffing box 'I5 packed with graphited asbestos cord, for example, produces a gas and liquid tight closure. A longer thread, as shown at 16, enables the operator with his long-shanked key to completely remove the inner tube closure member 53', which @poupee-macaron- I manner.

for groove engagement as shownin Figure fi.

several designs of blasting cartridges with impregnated'paperV or pasteboard outer casings particularly, although in certain instances the outer casing 20 was specified to be of iron.

' The applicant'has made up quantities of these casings, using strong brown paper, impregnating the same with a variety of pore closing, binding, and strengthening substances. In this comparatively simple appearing process of making paper cartridges there were many great and subtle diiliculties involved, not obvious at all to the casual inspector of the illustrations. or to the reader of this specification. The applicant believes that he is well on the conservative and true side when he The foregoing six illustrations have dealt with A states that comparatively few technologists and development engineers have had any practical experience in the production and handling of liquid nitrogen tetraoxide and of its actions, and still fewer.' if any at all, have had the combined vision and optimism in attempting to adapt paper cartridges or even metal cartridges to it in any form It would be regarded, applicant is sure, as especially optimistic and daring to attempt to use liquid nitrogen tetraoxide Aand a liquid hydrocarbon such as benzol in a paper or pasteboard cartridge.L

In this connection the applicant has conducted experimental development work with paper cartridges, not' only with liquid nitrogen tetraoxide containing various percentages of moisture ranging from 11e of one per cent moisture to fuming nitric acid of specific gravity 1.59 to 1.60. The addition of moisture it should be pointed out, to

liquid nitrogen tetraoxide produces therein the .most concentrated nitric acid, and iron, steel and aluminum are not only passive to liquid nitrogen tetraoxide but to concentrated nitric acid. The applicant has had the finest of iron wires immersed in liquid nitrogen tetraoxide and concentrated nitric acid respectively for long periods of time without chemical action, beyond that producing the passive state.

If it were not for the benzol and certain other liquid hydrocarbons, the problem of drying and impregnating paper cartridge cases would be a fairly simple one, because paraffin wax as well as certain gums and resins would serve to seal the liquid nitrogen tetraoxide and its impurities, but paran as well as certain gums and resins are soluble in benzol and certain other liquid hydrocarbons and therefore are ruled out. There are, however, certain particular resins which have proved interesting.

For certain time factors Bakelite varnishes v have been successful, as Well as a polystyrene sprayed, baked and polymerised at temperatures of from 150 to 180 Fahrenheit for a 24-hour period. Thus it will be appreciated by technologists that the art of designing and fashioning the new cartridges embodies certain manufacturing processes with working details to be mastered. Possibly due to suchl complications, together with lack of vision, in this undeveloped field, no one has yet successfully packaged a liquid explosive with liquid nitrogen tetraoxide as one of the constituents.

Liquid nitrogen tetraoxide and a liquid hydrocarbon such as benzol, for example, constitutes probably the most economic mixture of stored potential chemical energy possible. When liquid nitrogen tetraoxide and a liquid hydrocarbon such as benzol for example are mixed only three or four degrees centigrade are recorded indicating simply a temperature of mutual solution. There is no reaction or nitration and consequent release of any appreciable quantity of heat energy. When we mix alcohol and water we get ten orA fteen degrees rise centigrade in the mutual solution of these substances. When we nitrate glycerin or toluene, phenol and the like, we must carry o the thermal units of the chemical reactlon by a system of cooling water, in order to prevent an explosion, and naturally these thermal units are lost to any useful purpose.

In the liquid nitrogen tetraoxide plus liquid hydrocarbon mixtures, there is only the moderate temperature rise of mutual solution as set forth. Such mixtures as the applicant now proposes to package, in cartridge and canister form, carry inherently from the place of manufacture, which is` simple mixing of the component parts, tothe field of use, potentially stored for the blast of detonation, all of the many thermal units now thrown away in the cooling water in the conventional nitrating process at the factory in making the conventional explosives.

The applicant believes that he is the rst to develop, reduce to practice and produce a successful method, as well as ways and means for handling this complex and difiicult problem of cartridge packaging and in taking advantage of the foregoing chemical technology. In this connection, with the finished product, applicant naturally wishes to point out that foresight is much more diilicult than hindsight.

`With the foregoing exposition applicant returns to the specific phases of paper for such cartridge cases.

Paper consists largely of cellulose, and cellulose constitutes the framework of the vegetable kingdom and contains'considerable moisture.

'Furthermore cellulose reacts with nitric acid to form nitrates, which are commercially, as well as scientifically, called nitrocellulose, gun-cotton being one of them.

The lower nitrates of cellulose are called pyroxylin. Cellulose is hygroscopic and therefore contains water in practically every climate. Torender paper orpasteboard useful in cartridge casings for the particular compounds used in the present cartridges, the paper must be desiccated and the pores refilled with a substance or substances not readily-or rapidly attacked by benzol, nitro-benzene nor by liquid nitrogen tetraoxide, nor by nitric acid, nor by a mixture of these substances.

This pore-filling substance or substances in some cases may be a chemical base or alkali, to neutralize any nitric acid which may be inherent in the nitrogen tetraoxide orbe formed therein by moisture in the benzol, kerosene, carbon disulphide, or grease, for example.y Lime, potassium hydroxide, sodium hydroxide or the like may be well added.

Desiccated paper rolled and impregnated therefore with suitable chemical substances on a mandril forms the basis of a possible cheap and satof the casing'to prevent the absorption of moisture on storage. Among the plastics for interior coats may be mentioned condensation products l of phenol and formaldehyde in fluid form, polymerized to solid form by` baking.

Solutions of sodium silicate have been successfully used in the applicants experimental work in connection with his paper and pasteboard cartridge casings, driving out the waterpresent in the cellulose of the paper or pasteboard upon the completion of the casing before immersing, spraying, or painting with solutions of sodium silicate.

A properly treated silicated paper cartridge casi/ng may be fashioned to hold benzol and the likefor practically indefinite periods of time, and to resist liquid nitrogen tetraoxide and the small quantities. of concentrated nitric acid present when mixed with benzol and the like, for periods of time practical for safe blasting use. Solutions of sodium silicate are mildly alkaline and serve not only.as an excellent binder 1but as an excellent temporary or time factor barrier against liquid nitrogen tetraoxide and the small quantities of concentrated nitric acid which it from time to time contains.

Again very close and satisfactory timing ad- 'justments can. be made inthe binding and impregnating compounds for the allowance of the escape of the liquid nitrogen tetraoxide and disappearing, thereby rendering the explosive cartridge harmless. 'Ihis ultimate safety feature is analogous to the safety feature of liquid air or liquid oxygen and a combustible body when used as a safety explosive as previously explained.

In practice therefore I may elect to fashion the outer casing of a series of my cartridges to resist attack for predetermined periods of time after mixing the liquid nitrogen tetraoxide with the liquid or semi-liquid hydrocarbons, the cartridge becoming a harmless dud when the outer casing finally allows the liquid gas to pass through the walls and escape.

I have found that a 40% solution of sodium silicate is an exceedingly cheap and eillcient impregnating compound for this double safe, as well as the safe, fashioningof a pasteboard cartridge. The liquid nitrogen tetraoxide when, as and if it escapes, after a pre-determined period of time in the double safe design of cartridge, does not form dangerous pools or puddles, as in the case of nitroglycerin, which has leaked out of a can, but on the contrary, the liquid nitrogen tetraoxide escapes as a gas with an affinity for the moisture of the atmosphere, combining therewith and precipitating out as dilute nitric acid, which eventually in its outdoor use contributes to the formation of nitrates in the soil, which although minute of course is after all in action in the right direction, if, as and when used, for example, on a farm.'

With proper control of all of the materials entering into the structure of the outer casing, particularly with reference to dessication of the cellulose of the paper or pasteboard before impregnating, and proper drying after impregnating, if, as and when I use sodium silicate, it is possible to produce a casing with a controlled time factor in allowing the escape of liquid nitrogen tetraoxide after its admixture with one or more of the liquid hydrocarbons or other combustible bodies in the outer casing. This action is somewhat analogous to the design and fashioning of a time fuse possible only with the proper choice of charcoal and purity of saltpeter, all with controlled moisture, proper proportioning of the relative quantities of charcoal and saltpeter respectively, all taken in connection with the lacket" of the fuse. With proper control, therefore, time fuses may be made to burn at 12 various rates in seconds per inch. The present applicant's factors in his double safe design of blasting cartridge are but parallel analogies to those in a time fuse.

With further reference to Figure 7,' in this illustration 80 is a sheet metal can of iron, tinned iron, .or aluminum, for example, designed and constructed to withstand internal pressures of graded explosive mixtures at all temperatures likely to be met with in storage; and 8| is a suitable reinforcing band. 82 is a crown cap or a screw cap likewise of iron, tinned iron or aluminum, fashioned to be applied to the neck'member 83 of the can withpa liquid and gas tight nt; and .84 is an end of a tubular member 85, passing through an opening in the cap member 82, making therewith a liquid andgas tight combination as by soldering for example, using pure tin or lead-free solder therefor. 85' is a boss member of the cover member 88, said boss member tting snugly into an end of the tubular member 85; and," is a light flange member, in the closure member 88, comprising the boss member 88 bored out and threaded with a right-hand thread to receive the threaded end of the tension rod 88, threaded with a left-hand thread at the enlarged end of the tension rod terminating in the square or polygon shank 9|, free to revolve in a slight countersink 92, but with a shoulder 88 ground into the recess and adapted to make a liquid and gas tight fit with the interior of the boss member 85'.

Thus it will be seen that the tubular member 8l may be filled with liquid nitrogen tetraoxide, and through the agency of the closure members 86 and 8l, and the right and left-hand threads respectively upon the rod member 98, be locked hermetically within fthe interior of the can 88. A

key 62, shown in dotted lines, has a square or polygonal recess for the reception of the square or polygonal end member 8| of the rod member 90. It willbe seen and appreciated from an inspection of this construction that a few turns of this key will not only break the hermetic seal and .assist the vapor pressure of the nitrogen tetraoxide 48 in forcing open the chamber enclosing it, but lift the square or polygonal end 9| from its snug ground seat, and if the key is turned a suilicient number of additional turns, the election of the end closure member 88 is effected as wall as an admixture of the liquid nitrogen tetraoxide 40 with the benzol, gasolene, kerosene or grease 4l, and if the key is still further turned, the rod member 90 will lbe free and removable through the tubular member 85, and in consequence provide a vent thereinto for the vapor of the liquid nitrogen tetraoxide to escape in due time and thereby render the entire contents of the canister harmless.

With the removal of the key therefore, after the liquid nitrogen tetraoxide boils away more slowly at the lower temperatures.

In the place of benzol, nitro-benzene, gasolene, kerosene, or grease, for example, as indicated in the dotted lines 4I, I may elect to use one of my comparatively insensitive and comparatively low- 75 powered mixtures of one or more of .these com- 13 bustible bodies with a limited volume of liquid nitrogen tetraoxide dissolved therein, the said mixture or solution being converted into a. relatively sensitive and relatively high-powered explosive by the addition of more liquid tetraoxide thereto, as set forth in my previously filed copending patent application already referred to. According to my teaching for designing and fashioni/ng a. leak-proof cartridge and canistenfor the liquid gas, which I completely surround in my structures, I may elect to add a pre-determined quantity of normal or iso-butane to the benzol, nitro-benzen gasolene, kerosene or grease, in order to bring the vapor pressure of such combustible, or mixture of combustibles, just up to, or in excess of, the vapor pressure of the liquid nitrogen tetraoxide. Since normal and/or iso-butano have lower boiling points than the liquid nitrogen tetraoxide, the hydrostatic pressures are controlled by the vapor pressures in such a, system, and the scientific principle brought to bear in mynew cartridge or canistel will be appreciated.

With further reference to Figure 8:

Here the metal canister is similar to that shownl in the preceding illustration, but with a modied detonator well-way, which in this case is a deep drawn thimble of suitable metal passive to the liquid gas. being closed at an end 9 5 and extending into the explosive, liquid mixture |99,

or mutual solution of one or more combustibles with the liquid nitrogen tetraoxide.

With further reference to Figure 9:

Here a transverse cross section through Figure 'l is given, the several arrows showing the hydrostatic balance set up between the liquids in the outer and inner compartments respectively, through the calculated or experimentally determined addition of the butane or iso-butane to the outer mixture.

With further reference to Figure 10:

Here a detonator well-way detail is set forth showingone 'ofmymethodsofinserting adeepdrawn electrolytic iron thimble 95 into the metal cap 82 and in providing a liquid and gas tight union by expanding as shown at 91 internally and at l5 externally.

Where as the applicant has illustrated and described several designs of safe, and double safe, blasting cartridges and blasting canisters respectively. as well as ways and means of producing and operating them, using liquid and semiliquid filler components of a liquid or fluid explosive, it is possible that those skilled in the several arts and sciences involved may further vary the d, ways and means. as well as methods.

as disclosed without departing from the spirit of this invention, and it is therefore not desired to be limited to the foregoing teachings except as may be called for in the claims.

Having described my invention, I claim:

1. An explosive device. comprising a casing hermetically enclosing a liquid combustible body. a closed chamborsubstantially centrally disposed inandsurroundedbythecombustiblebodyin said casing, said chamber containing a quantity of liquid nitrogen totraoxide which when admixed with the combustible body in-said casing produces a liquid explosive, means operable from outside said casing to open said chamber to bring about such admixture. and a vent for said casing. said vent opened by an element of the chamberopening means.

2. An explosive device, comprising a casing hermetically enclosing a liquid component of a liquid explosive mixture, a closed chamber disposed within said casing and having therein another liquid component of the liquid explosive mixture, the liquid components when admixed forming the explosive mixture, a vent for said casing in substantial alignment with said chamber, said chamber comprising a movable wall, chamber-opening means comprising a member having operable engagement with said wall for moving said wall into chamber-opening position to bring about such admixture of the liquid components, said member extending into said vent for controlling the same.

3. A hermetically sealed lai-compartment high explosive producing device, comprising one closed chamber containing a mixture of liquid combustible ingredients, said ingredients being in such proportions to each other as to produce a relatively insensitive and low powered explosive; a second closed chamber disposed coaxially within the rst named chamber and containing the requisite amount of one of said liquid ingredients which, when added to said mixture, will change the said proportions to produce a relatively sensitive and high powered explosive mixture; a vent disposed in an end wall of said first named .chamber, said vent for .the relief of pressure generated in said chamber; and chamber-opening means for causing the liquid of one chamber to mix with the liquid of the other chamber to obtain such change of proportions, said means comprising a. shaft passing coaxially through the inner chamber, one end of said 'shaft operatively engaging said vent for controlling the same.

Nnvn. Mormon norms.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 675,708 Blackwell June 4. 1901 684,897 Lloyd Oct. 15,' 1901 2,159,531 Polin May 23, 1939 2.263.179 Benton Dec. 30, 1941 1,531,555 Harris et al. Mar. 31, 1925 2.043.565 Weber June 9, 1936 1,147,622 Butcher July 2 0. 1915 325,538 Hayes Sept. l, 1885 612,495 Hathaway Oct. 18, 1898 572,401 Bakewell Dec. 1, 1896 2,298,255 Hopkins Oct. 8, 1942 1,298,500 Hamel Mar. 25. 1919 FOREIGN PA'IENTS Number Country Date 1,481 Great Britain 1.882 16,586` Great Britain 1912 creat prima 191s 

